The disclosure relates to a valve for installing in a valve bore. The disclosure relates furthermore to an assembly method for a valve of this type.
Under the designation 2/2 directional cartridge valves, Bosch Rexroth AG supplies seat valves or seat slide valves, as per data sheets RD 21010 and RD 21050, which are constructed from a valve bushing for inserting into an installation bore according to DIN ISO 7368 and from a control cover closing off the installation bore. The spring space of a valve piston inserted into the valve bushing is activated by means of control channels present in the control cover and optionally by a pilot control valve arrangements. Advantages of said valve systems, which are also referred to as logic valves or single-stage logic valves, include the high degree of variability, the robust structure and the cost-effective production even given a high nominal volumetric flow. The development of said concept has led to the construction of “active logic valves”—also two-stage and three-stage logic valves of an extended valve piston which projects into the control cover and on which an actuating piston is formed, said actuating piston making available further surfaces for the hydraulic displacement of the valve piston. Said further surfaces can be used, for example, for a rapid opening operation or closing operation which can be executed independently of the pressures in the valve bore.
Conventional active logic valves frequently have a valve bushing which is extended into the control cover and which receives the full extent of the valve piston, as shown in EP 0 798 471 B1. This reduces the available control cross sections and therefore the maximum nominal volumetric flow of the valve due to the wall thicknesses required at the valve bushing given a predetermined installation bore (also valve bore below).
It is true that other active logic valves guide the actuating piston of the valve piston in the control cover, for example the valves “active cartridge valves—monitored, series C13DCC and C18DCC” of Parker Hannifin Corporation, Ohio, USA, depicted in the catalogue HY14-3201/US. However, the control cover is difficult to manufacture due to the multiplicity of channels. The spring which is to be mounted in the control cover prevents the cover and valve bushing from being provided as a preassembled constructional unit. Lower piece numbers in comparison to the single-stage logic valves are required, this rendering the production of the control cover, valve bushing and valve piston components, which each differ in comparison to the single-stage logic valves, disproportionately expensive. Provision of functional variants is associated with a high outlay, since the individual components would have to be changed per se for this purpose.